The reserves of molybdenum on Earth are relatively small, accounting for only 0.001% of the weight of the Earth's crust. The total reserves of molybdenum ore are about 15 million tons, mainly distributed in countries such as the United States, China, Chile, Russia, and Canada. The proven reserves of molybdenum metal in China are 1.72 million tons, with a basic reserve of 3.43 million tons, ranking second only to the United States in the world. Molybdenum mines are concentrated in four provinces, including Shaanxi, Henan, Jilin, and Liaoning. There are six super large molybdenum mines with metal reserves of over 500000 tons in the world, and China's three major molybdenum mines, Luanchuan in Henan, Daheishan in Jilin, and Jinduicheng in Shaanxi, are listed.
The abundant molybdenum resources provide extremely favorable conditions and solid foundation for China's development of molybdenum smelting and processing, and vigorously promote the application of molybdenum.
Molybdenum, like tungsten, is a refractory rare metal. Molybdenum has a melting point of 2620 ℃, and its strength is high at both room and high temperatures due to its strong interatomic bonding. It has a small coefficient of expansion, high conductivity, and good thermal conductivity. At room temperature, it does not react with hydrochloric acid, hydrofluoric acid, or alkaline solutions, but only dissolves in nitric acid, aqua regia, or concentrated sulfuric acid. It is also quite stable for most liquid metals, non-metallic slag, and molten glass.
Therefore, molybdenum and its alloys have extensive applications and good prospects in important sectors such as metallurgy, agriculture, electrical, chemical, environmental protection, and aerospace, becoming an important raw material and irreplaceable strategic substance in the national economy.
The Mining and Usage Status of Molybdenum in China
In recent years, there has been rapid development in the mining, smelting, and processing of molybdenum in China.
According to information, in 2001, China actually produced 72000 tons of molybdenum concentrate, 33000 tons of molybdenum oxide, 7600 tons of molybdenum iron, 9500 tons of various ammonium molybdate, 1183 tons of molybdenum bars, 1200 tons of molybdenum slabs, 150 tons of molybdenum plates, over 40 tons of molybdenum discs, about 50 tons of molybdenum tips and other shaped products, 3.15 billion meters of molybdenum wire in the electric light source industry and mechanical processing, as well as hundreds of tons of chemical products such as lubricants, catalysts, pigments, etc.
Moreover, China occupies a pivotal position in the world molybdenum market. According to customs statistics, in 2001, China exported 70274 tons of molybdenum ore calcine, molybdate, ferromolybdenum and other molybdenum products, earning foreign exchange of 262 million dollars.
The consumption form of molybdenum is mainly industrial molybdenum trioxide, accounting for about 70%, ferromolybdenum accounts for about 20%, and metal molybdenum and molybdenum chemical products each account for 5%. Its application fields and distribution proportion are roughly as follows: steel smelting consumption accounts for about 80% (including alloy steel consumption of about 43%, stainless steel consumption of about 23%, tool steel and high-speed steel consumption of about 8%, cast iron and rolling steel consumption of about 6%), chemical products consumption of about 10%, metal molybdenum products consumption of about 6%, high-temperature high-strength alloys and special alloys consumption of about 3%, and other molybdenum products consumption of about 1%. From the above, it can be seen that the development of the steel industry plays a decisive role in the consumption of molybdenum. However, with the development of science and technology, the application of molybdenum in high-tech and other fields will continue to expand and develop.
According to the consumption statistics of molybdenum in various countries around the world, the application of molybdenum in the steel industry still occupies a major position. Molybdenum, as an alloying element in steel, can improve its strength, especially at high temperatures and toughness; Improve the corrosion resistance of steel in acid alkali solutions and liquid metals; Improve the wear resistance and hardenability, weldability, and heat resistance of steel. Molybdenum is a good element for forming carbides and does not oxidize during the steelmaking process. It can be used alone or in conjunction with other alloy elements. The molybdenum consumption of special steel is increasing regularly, and currently the molybdenum consumption per ton of special steel has reached the level of 0.201 kilograms.
Molybdenum, along with chromium, nickel, manganese, and silicon, can be used to manufacture different types of stainless steel, tool steel, high-speed steel, and alloy steel. The stainless steel produced has good corrosion resistance and can be used as a corrosion-resistant steel pipe for oil extraction. A type of stainless steel with about 6% molybdenum can also replace titanium for seawater desalination devices, ocean going ships, and offshore oil and gas extraction pipelines. This type of stainless steel can also be used for car casings, sewage treatment equipment, etc. The efficiency of molybdenum containing tool steel is twice that of tungsten tools, with excellent performance, low cost, and light weight. The molybdenum series high-speed steel has advantages such as non-uniformity of carbides, wear resistance, good toughness, and strong high-temperature plasticity, making it suitable for manufacturing formed cutting tools. Molybdenum containing alloy steel can be used for manufacturing machine tool structural components, industrial vehicles, and bulldozers. Molybdenum containing alloy steel with fine pearlite structure in the rolled state is an important steel in rail and bridge construction.
Molybdenum, as an alloy additive for iron, helps to form a completely pearlite matrix, improves the strength and toughness of cast iron, improves the uniformity of the microstructure of large castings, and also improves the hardenability of heat treated castings. Molybdenum containing gray iron has good wear resistance and can be used as brake wheel and brake pad of heavy vehicles.